Puerto Rico has shown a steady increase in cancer statistics during the past decades. It is expected to reach close to 9,000 new cancer cases by the turn of the century. Unfortunately, the health care delivery system is the island has not matched that trend. The result is a high incidence of cervical, endometrial and tobacco-related malignancies. Equally important the cancer death rate is higher from lung, liver, stomach, head and neck, esophagus and other sites. For the year 2000 population census, the Island of Puerto Rico is expected to show a population of 3.91 million. Close to 2.0 million are considered to be medically uninsured and indigent. For decades the PR state and municipal government were the largest direct care providers of health services in the island. Health care was provided utilizing a system of primary, secondary, tertiary and supratertiary institutions throughout the island. Supratertiary cancer care was given at strategically placed institutions and university hospitals in large medical centers. During the past 6 years, the government of PR began a revolutionary health care reform that based health care on a health maintenance organization (HMO) system. The goals of the San Juan MBCCOP are to expand and strengthen quality cancer control and treatment research in a changing medical environment in the community; to provide access to state-of-the-art cancer control and treatments; to provide educational and informational activities to health care providers throughout the island; to evaluate selected issues of the MBCCOP performance in this setting. The San Juan MBCCOP is located at the San Juan City Municipal Hospital in the PR Medical Center. The other main participating institutions are the San Juan Veterans Hospital and the San Juan Oncologic Hospital. The major affiliates are the PR GI Institute and the Hato Rey Hematology/Oncology Associates. Together, these institutions care for more than 2,000 new cancer patients per year.